Like soldiers snapping to attention, the light fixtures come on one by one as you walk through Palmer-Donavin's warehouse in Columbus, Ohio. President and COO Ronald Calhoun had motion sensors installed to assure that the lights would draw power only when needed. He expects to recoup his investment in three years.

Palmer-Donavin isn't the only business to have found that changing how it light its facilities is the quickest, easiest, and most cost-effective way many building materials suppliers can burnish their green credentials and save money at the same time. Among other examples:

Canby Builders Supply in Canby, Ore., replaced all its warehouse lights with energy-efficient lighting. Despite using one-third fewer fixtures than before, the space is more brightly lit. The change trims $300 a month from Canby's power bill.

Nearby, in the Portland suburb of Hillsboro, Ore., Parr Lumber spent $250,000 this year to install better lighting in 16 sites. The $37,000 a year that Parr saves in energy costs would normally suggest a 6 1/2-year payback, but thanks to an $80,000 tax credit and $60,000 in incentives from the local utility, Parr should recoup its costs in three years.

BigHorn Building Materials in Silverthorne, Colo., reduced its warehouse lighting costs by 80% using installed insulated skylights and large pane windows.

McCoy's Building Supply in San Marcos, Texas, is configuring its new headquarters to use as much natural light as possible.

After GreenDepot brought in a consultant to review ways to employ natural and fluorescent lighting at its Brooklyn, N.Y., facility, the company found employees felt less tired and got fewer headaches.

Lights typically suck up one-third of the electricity used in commercial buildings. Lumberyards, which are as much (or more) outdoor businesses as indoor businesses, are likely to be less dependent on artificial lights, but those bulbs still figure into the overhead, economically and literally.

And that price is expected to climb. Retail electricity prices jumped 10.1% in 2006, grew another 2.1% in 2007, and likely will climb 1.7% this year, the Energy Department estimates. But local prices vary markedly. A kilowatt-hour's worth of juice in Hawaii costs more than four times what it does in Idaho. This means that while all LBM dealers can benefit from green lighting initiatives, some will get a quicker payback than others.

The first change to consider is replacing older lighting, usually T12 fluorescent lamps, with T8 lamps in office settings and T5 lamps when the lights are at least 30 feet up. At typical electricity costs of 10 cents per kilowatt-hour, these newer, super-efficient bulbs pay for themselves in two to four years.

And in areas where there are regular incandescent bulbs, compact fluorescent lights (CFLs) are the way to go. Swapping out an incandescent bulb for a CFL can save about $30 or more over its lifetime, according to the government's Energy Star program. Fluorescent lights also generate less heat than incandescents, so you're not taxing the air conditioning system.

Can't stand to toss an incandescent bulb that hasn't burned out? Clean it; doing so will make it burn 10% to 60% brighter, according to the Energy Department.

Look, too, at occupancy sensors, which turn off lights if no one is in an area. These work in spaces used infrequently, such as bathrooms, and in places that see extensive use only at certain times of day, such as warehouses. Timers eliminate the need to have the last person working turn off the lights when he leaves, and photocells, which sense the amount of natural light and adjust electrical light accordingly, work in areas with a lot of daylight.

All told, these controls can reduce energy consumption by 50% or more, the Energy Department says.

Some utilities will give rebates to companies that become more energy efficient, will help companies be more energy efficient, and will buy back the excess power that a company generates. For information on programs in your area, visit North Carolina State University's DSIRE–a Database of State Incentives for Renewables & Efficiency–at The Energy Policy Act of 2005, much of which was updated in the comprehensive energy bill signed into law in December, also offers commercial tax breaks for purchasing qualified energy-efficient equipment, building energy-efficient buildings, or improving the energy efficiency of an existing building.

Experts stress that to benefit fully, a business should consult a lighting designer. "Lighting is what we call an energy-affective system," says John Bachner, communications director at the National Lighting Bureau. "How you use lighting affects many things," including heating and cooling loads. And studies have shown that more effective lighting can boost safety, sales, and productivity.

Green Depot, a retailer and distributor of green building products that's closely linked to Marjam Supply Co., went to its utility, National Grid, for help with revamping energy efficiency in its Brooklyn, N.Y., location. "We had National Grid come in and provide us with an expert that changed out lights and light switches to fluorescents," says Carmen Arguelles, COO of Marjam and president of Green Depot. Arguelles says that after using fluorescent light and natural light, workers' eyes got less tired and people got fewer headaches.

Art Johnson, vice president of store development for McCoy's, is looking to hire an energy management company for McCoy's headquarters project. "If I had to do it over, I would interview and hire an energy management company from the very beginning," he says. "The technology is changing so fast, it's hard to keep up with it."

Skylights are an example of an old idea–letting in natural light–that has improved significantly in recent years. Solar tubes, or sun tubes, can bring natural light into enclosed or hard-to-reach spaces. Also consider light shelves, interior or exterior, that can bounce daylight deeper into a building, says Brendan Owens, director of LEED technical development. Overhangs help let in light and heat during the winter and block the sun during the summer.

Also, keep in mind that the choice of window glass matters. Large windows can provide a good amount of natural light, but they should have some kind of covering to lessen glare during certain times of the day.

–Victoria Markovitz